The present invention relates to a gas turbine engine of the type having means for determining the inside temperature of a combustion chamber and controlling various kinds of functions in accord with the determined inside temperature of the combustion chamber.
Generally, it is important to control a gas turbine engine based on an inside temperature of its combustion chamber.
For example, if the temperature inside the combustion rises higher than the nominal operating value, the emission becomes worse and, if the temperature is held at an extreme high temperature for a long time, the combustion chamber and the turbine may be damaged. Therefore, it is necessary to emergently stop the engine or restrict the fuel flow rate if the inside temperature of the combustion chamber abnormally increases.
If flameout (extinction) occurs during the operation of the engine, one is requested to immediately re-ignite the engine by using the ignition device. It is therefore desirable to reliably re-ignite the engine by early detecting the flameout state from a decrease in the inside-temperature of the combustion chamber.
However, an attempt of directly detecting the inside temperature of the combustion chamber by using a temperature sensor mounted therein may complicate the design of the engine and requires a severe layout of an especially high-heat-resistant temperature sensor.
Japanese Laid-Open Patent Publication No. 7-243337 discloses a method for indirectly determining an inside temperature of a combustion chamber from the number of revolutions of the engine at a compressor-inlet-temperature measured by a temperature sensor for the purpose of normalizing a preheating time of a glow plug.
This method, however, requires placing a high- heat-resistant temperature-sensor at a compressor portion inside the engine, complicating the layout design of the engine components.
Namely, the prior arts use special designed temperature sensors near or in the inside the combustion chamber to determine the inside-temperature necessary for controlling the engine operation, but they have a disadvantage of complicating the arrangement of components and the construction of the engine itself.
To solve the above-mentioned problem, the present invention was made to provide a gas turbine engine having means capable of controlling various kinds of operations in accord with an inside temperature of a combustion chamber, which can determine the inside temperature of the combustion chamber by using an existing heating coil of a glow plug as a heat-sensitive resistive element without placing any additional specially-designed temperature sensor in such a manner that a resistance-value of the glow plug driven with a constant current is detected by the heating coil and a temperature corresponding to an inside-temperature of the combustion chamber at the measured glow-plug resistance-value is determined from a table of preset glow-plug resistance-temperature characteristics predetermined for parameters being airflow or fuel-flow rate varying within a specified range.